wait-for-dep

Waits for a dependency before continuing. It's ment to be used in startup scripts like Docker's entrypoint.

Installing

pip install wait-for-dep

Usage

wait-for-dep dependency-url-1 dependency-url-2 ... dependency-url-n

ie:

wait-for-dep https://my-server/healthz/ psql://user@db-host/db-name

Available checks

HTTP(s)

HTTP and HTTPS are available by default. Follows redirects; only response with HTTP code 2XX is accepted as valid.

Accepted URL schemas

• http://
• https://

Example

wait-for-dep https://my-server/healthz/ http://my-server/healthz/

PostgreSQL

RDBMS has to accept connection and allow to perform simple SELECT query.

Installation

pip install wait-for-dep[postgres]

Accepted URL schemas

• postgres://
• postgresql://
• psql://

Example

wait-for-dep psql://admin:password@db-host/db_name

MySQL

RDBMS has to accept connection and allow to perform simple SELECT query.

Installation

pip install wait-for-dep[mysql]

Accepted URL schemas

• mysql://

Example

wait-for-dep mysql://admin:password@db-host/db_name

Redis

Rdis has to accept connection to selected database (defaults to 0).

Installation

pip install wait-for-dep[redis]

Accepted URL schemas

• redis://

Example

wait-for-dep redis://redis-host/5

Memcached

Memcached has to accept connection.

Installation

pip install wait-for-dep[memcached]

Accepted URL schemas

• memcached://

Example

wait-for-dep memcached://memcached-host/

MongoDB

MongoDB has to accept connection.

Installation

pip install wait-for-dep[mongodb]

Accepted URL schemas

• mongodb://

Example

wait-for-dep mongodb://admin:password@db-host/db_name

RabbitMQ

RabbitMQ has to accept connection to given vhost. You can use optional querystring params require_queue and require_exchange to additionaly check if particular queue or exchange exists (check will fail otherwise).

Installation

pip install wait-for-dep[amqp]

Accepted URL schemas

• amqp://

Example

wait-for-dep amqp://admin:password@rabbit-host/vhost
wait-for-dep amqp://admin:password@rabbit-host/vhost?require_queue=myqueue
wait-for-dep amqp://admin:password@rabbit-host/vhost?require_exchange=myexchange
wait-for-dep amqp://admin:password@rabbit-host/vhost?require_exchange=myexchange&require_exchange=mysecondexchange&require_queue=myqueue&require_queue=mysecondqueue

Apache Kafka

Kafka has to accept connection. In HA mode (node count > 1) only one node is required to accept the connection.

Installation

pip install wait-for-dep[kafka]

Accepted URL schemas

• kafka://

Example

wait-for-dep kafka://kafka-host/
wait-for-dep kafka://kafka-first-host/,kafka://kafka-second-host/

TCP

Plain TCP is available by default. Service port is required.

Accepted URL schemas

• tcp://

Example

wait-for-dep tcp://my-server:7624

Unix

Unix sockets are available by default.

Accepted URL schemas

• unix://

Example

wait-for-dep unix:///var/run/docker.sock